"This has been a real perfect day ... America feels like a second home to us," Liam Payne said onstage with his bandmates when they won the night's first award. The group released its new album, "Four," last week.

"To the fans who went out and bought over a million copies of my last three albums, what you did by going out and investing in music and albums is you're saying you believe in the same thing I believe in – that music is valuable and that music should be consumed in albums and albums should be consumed as art and appreciated," said Swift, who recently removed her music from streaming service Spotify.

Brantley Gilbert, who won favorite album – country for "Just as I Am," is on the same label as Swift, Big Machine Records. He also removed his music from Spotify, but declined to discuss the topic when asked about it backstage.

"You know tonight for me was about the songs and the fans and I had a blast accepting an award, I'm not so sure I want to chase the question without a safe answer," he told reporters.

Azalea, who was the top nominee with six, performed twice: She hit the stage first for "Fancy" and new single "Beg for It," later returning to close the show with Jennifer Lopez.

Azalea won favorite album – rap/hip-hop for "The New Classic" and favorite artist – rap/hip-hop.

"It means so much to me that it is for best hip-hop because that's what inspired me to move to America and pursue my dreams, and it's what helped me when I was a teenager to escape and to get through my life and to better times," the 24-year-old Australian rapper said as her mentor T.I. stood beside her. "And it means so much that I can stand here against Eminem and Drake and come out with this."

Ariana Grande also worked double duty Sunday: She took the stage to sing lounge-y, piano-versions of her upbeat hits "Problem" and "Break Free," following that with a duet of her latest hit, "Love Me Harder," with the Weeknd. Grande's older brother jumped up in joy, MAGIC! leader Nasir Atweh sang along, and Heidi Klum bopped her head.

Grande returned again to sing "Bang Bang" with Nicki Minaj and Jessie J, who kicked off the song in the crowd. She sang closely in front of her boyfriend, R&B singer Luke James and danced next to Swift and Sam Smith.

Smith, who also performed "I'm Not the Only One" with A$AP Rocky, won favorite male artist – pop/rock.

"Last year I wrote an album about being lonely and tonight, I couldn't feel further from lonely, so thank you so much," he told the crowd after thanking his fans.

Mary J. Blige performed "Therapy," a new song she wrote with Smith, and host Pitbull performed with R&B singer Ne-Yo. Fergie gave a hip-hop flavored performance of her comeback single, "L.A. Love (La La)," while Selena Gomez slowed it down for the emotional "Heart Wants What It Wants." And Imagine Dragons, who won favorite artist — alternative rock for a second time — performed their new folky single, "I Bet My Life."

Australian boy band 5 Seconds of Summer won new artist of the year, beating out Azalea, Smith, Meghan Trainor, and Bastille. They also performed a cover of the Romantics' "What I Like About You."

"Being from Sydney, you never think you're going to win an American Music Award, so it's the coolest thing ever to us," band member Ashton Irwin said backstage.

Bryan, who introduced a satellite performance from Garth Brooks, took home favorite male artist – country.

Perry won single of the year for her No. 1 hit "Dark Horse," favorite female artist – pop/rock and favorite artist – adult contemporary. Other absent winners included Carrie Underwood, John Legend, and Beyonce, who won two awards.

The soundtrack for "Frozen," the year's top-selling album, won top soundtrack.